1. Field of the Invention
The invention relates to a one-way clutch and a power generating apparatus.
2. Description of Related Art
There are known some conventional wind power generators in which a main shaft connected to blades is rotated upon reception of wind force and the speed of rotation transmitted from the main shaft is increased by a speed increaser to drive a generator (for example, see Japanese Patent Application Publication No. 2007-232186 (JP 2007-232186 A)). In such wind power generators, there is a problem that the speed of the rotation transmitted to the generator from the blades via the speed increaser changes due to a change in wind speed or wind direction and, as a result, power generation efficiency decreases.
Thus, the applicant has already suggested a wind power generator in which a one-way clutch is arranged between a speed increaser and a generator in order to improve power generation efficiency (Japanese Patent Application No. 2011-198354, and, hereinafter, referred to as “related invention”). In the wind power generator, even when the wind speed, or the like, changes and the speed of rotation of the main shaft reduces, the drive shaft of the generator continues rotating by inertia without a steep reduction in speed by interrupting connection between the output shaft of the speed increaser and the drive shaft of the generator with the use of the one-way clutch, so the average rotation speed of the drive shaft increases, and it is possible to improve power generation efficiency.
As shown in FIG. 11, the one-way clutch according to the related invention includes an inner ring 101, an outer ring 102, a plurality of rollers 103, an annular cage 104 and a plurality of elastic members 105. The rollers 103 are arranged between an outer periphery 101a of the inner ring 101 and an inner periphery 102a of the outer ring 102. The cage 104 retains the rollers 103 at predetermined intervals in the circumferential direction. The elastic members 105 elastically urge the corresponding rollers in one direction. The cage 104 is integrally formed of a pair of axially facing annular portions 104a and a plurality of cage bar portions 104b that couples both annular portions 104a. Each of a plurality of pockets 104c is defined by both annular portions 104a and any adjacent two cage bar portions 104b, and each roller 103 and each elastic member 105 are individually accommodated in a corresponding one of the pockets 104c. In addition, each cage bar portion 104b is formed integrally with a protrusion 104d that serves as a guide at the time when the corresponding elastic member 105 is arranged in the corresponding pocket 104c. 
The cage 104 that constitutes the one-way clutch according to the related invention has a complex shape such that the pockets 104c are formed by the annular portions 104a and the cage bar portions 104b and the protrusions 104d are respectively formed on the cage bar portions 104b. Therefore, it is not preferable to employ a method of manufacturing the cage 104 as an integral unit by machining, because manufacturing cost increases. In addition, a method of manufacturing an integral unit through injection molding of a synthetic resin material is conceivable; however, the cage 104 that is used in a power generating apparatus has a large size, so it is difficult to mold such the large-sized cage 104 with the use of an injection molding machine.